Sei Janet J, Ochoa Amanda S, Bishop Elizabeth, Barlow John W, Golde William T
Plum Island Animal Disease Center, Agricultural Research Service, USDA, Greenport, New York, United States of America; Department of Animal Sciences, University of Vermont, Burlington, Vermont, United States of America.
Department of Animal Sciences, University of Vermont, Burlington, Vermont, United States of America.
PLoS One. 2014 Oct 8;9(10):e109273. doi: 10.1371/journal.pone.0109273. eCollection 2014.
Dendritic cells (DC) are multi-functional cells that bridge the gap between innate and adaptive immune systems. In bovine, significant information is lacking on the precise identity and role of peripheral blood DC subsets. In this study, we identify and characterize bovine peripheral blood DC subsets directly ex vivo, without further in vitro manipulation. Multi-color flow cytometric analysis revealed that three DC subsets could be identified. Bovine plasmacytoid DC were phenotypically identified by a unique pattern of cell surface protein expression including CD4, exhibited an extensive endoplasmic reticulum and Golgi apparatus, efficiently internalized and degraded exogenous antigen, and were the only peripheral blood cells specialized in the production of type I IFN following activation with Toll-like receptor (TLR) agonists. Conventional DC were identified by expression of a different pattern of cell surface proteins including CD11c, MHC class II, and CD80, among others, the display of extensive dendritic protrusions on their plasma membrane, expression of very high levels of MHC class II and co-stimulatory molecules, efficient internalization and degradation of exogenous antigen, and ready production of detectable levels of TNF-alpha in response to TLR activation. Our investigations also revealed a third novel DC subset that may be a precursor of conventional DC that were MHC class II+ and CD11c-. These cells exhibited a smooth plasma membrane with a rounded nucleus, produced TNF-alpha in response to TLR-activation (albeit lower than CD11c+ DC), and were the least efficient in internalization/degradation of exogenous antigen. These studies define three bovine blood DC subsets with distinct phenotypic and functional characteristics which can be analyzed during immune responses to pathogens and vaccinations of cattle.
树突状细胞（DC）是连接先天性和适应性免疫系统的多功能细胞。在牛中，关于外周血DC亚群的确切身份和作用缺乏重要信息。在本研究中，我们直接在体外鉴定并表征牛外周血DC亚群，无需进一步的体外操作。多色流式细胞术分析显示可鉴定出三个DC亚群。牛浆细胞样DC通过包括CD4在内的独特细胞表面蛋白表达模式在表型上得以鉴定，具有广泛的内质网和高尔基体，能有效内化和降解外源性抗原，并且是在用Toll样受体（TLR）激动剂激活后唯一专门产生I型干扰素的外周血细胞。常规DC通过包括CD11c、MHC II类分子和CD80等不同的细胞表面蛋白表达模式来鉴定，其质膜上显示出广泛的树突状突起，表达非常高水平的MHC II类分子和共刺激分子，能有效内化和降解外源性抗原，并在响应TLR激活时能快速产生可检测水平的肿瘤坏死因子-α。我们的研究还揭示了第三个新型DC亚群，它可能是MHC II类分子阳性和CD11c阴性的常规DC的前体。这些细胞具有光滑的质膜和圆形的细胞核，在响应TLR激活时产生肿瘤坏死因子-α（尽管低于CD11c阳性DC），并且在外源性抗原的内化/降解方面效率最低。这些研究定义了三个具有不同表型和功能特征的牛血液DC亚群，可在牛对病原体的免疫反应和疫苗接种过程中进行分析。
